This disclosure relates to a device for an optical system that works with an intermediate image and comprises a stop with an associated aperture.
In various advanced applications, for example military applications, where sights, telescopes, electro-optical TV cameras, etc are used, the use of optical systems of this type is already known. The optical system can work, for example, within the visual range and the infrared range, that is with wavelengths within the range 0.45-14 micrometres. In connection with this, reference is made to the patent literature and the known systems on the market. By light is meant in this application at least a wavelength range 0.3-30 μm, comprising visible light and such wavelengths within the ultraviolet and infrared range that can be handled by optical technology used for the visible range.
With this type of optical system there is a pronounced desire to be able to design the system in such a way that it does not reveal itself during use. The problem is here that there are difficulties in avoiding stray light and reflections that can be detected by detection equipment, for example laser radar. The invention intends to solve this problem and proposes in this respect that the stray light and reflections in question should at least be reduced considerably. In connection with this, beam-reflecting surfaces (mirror surfaces) are used in one embodiment, and there is a desire to be able to arrange these surfaces in such a way that an optical system is obtained that is exceptionally difficult to detect. The invention also intends to solve this problem.